ES2272750T3 - A PROCEDURE FOR THE PRODUCTION OF TRIPTANE. - Google Patents

Abstract

A process for the production of triptane, comprises: providing a hydrocarbon feedstock comprising at least 1 vol % of at least one cyclic hydrocarbon comprising a C<SUB>5 </SUB>and/or C<SUB>6 </SUB>ring; pre-treating the hydrocarbon feedstock by contacting the hydrocarbon feedstock with a catalyst in the presence of hydrogen, under conditions suitable for selectively opening the ring of the cyclic hydrocarbon; and isomerising the pre-treated feedstock by contacting the pre-treated feedstock with an isomerisation catalyst to produce a triptane-containing product stream.

Description

A procedure for the production of triptane

The present invention relates to a Improved procedure for the production of triptane.

The triptane, or 2,2,2-trimethylbutane, is a hydrocarbon that is useful in the production of unleaded gasoline from engines and aviation (see WO 98/22556 and WO 99/49003). Its structure highly branched makes it particularly useful for boosting the index of octane engine (MON) fuel.

Various methods are known for the production of triptane, for example, as described in US-A-3878261. For example, him Tryptan can be produced by reacting a material of hydrocarbon feed, such as naphtha, with a catalyst of isomerization (US 3 766 286 and GB 0024888.0, published as WO 2/31089).

Typically, the feedstocks of Naphtha comprise non-cyclic paraffins, as well as hydrocarbons cyclics such as naphthenes and aromatic compounds. Under the reaction conditions, non-cyclic paraffins in the material Naphtha feed easily isomerized in hydrocarbons highly branched, such as triptane.

It has been found that cyclic compounds are more prone to side reactions and hence less prone to become the desired triptane product.

In accordance with the present invention, provides a procedure for the production of triptane, said procedure comprising:

provide a hydrocarbon feedstock comprising at least 1% in moles of at least one cyclic hydrocarbon comprising a ring C 5 and / or C 6;

preheat the hydrocarbon feed material by contacting the hydrocarbon feedstock with a catalyst in presence of hydrogen, under suitable conditions to open selectively the cyclic hydrocarbon ring; and

isomerize the pretreated feed material by contacting the material feed pretreated with an isomerization catalyst to produce a product stream containing triptane.

The hydrocarbon feedstock can be a hydrocarbon stream that boils in the range of 50 to 110 ° C. Preferably, the hydrocarbon stream has a boiling range of 60 to 105 ° C, more preferably 75 to 100 ° C The hydrocarbon stream can be a stream of rented or, preferably, a stream of naphtha. Plus preferably, the naphtha stream is a naphtha stream that it comprises at least 30% by weight, preferably at least 50% in weight, for example 60 to 90% by weight, of C7 hydrocarbons.

The hydrocarbon feed material comprises at least 1% by volume of at least one cyclic hydrocarbon  which has a C5 and / or C6 ring. Preferably, the hydrocarbon feedstock comprises 2 to 60% in volume, more preferably 5 to 40% by volume and more preferably from 10 to 30% by volume of at least one hydrocarbon cyclic having a C5 and / or C6 ring. Hydrocarbons Cyclics that may be present include naphthenes and compounds aromatic Such compounds may be substituted by for example, with alkyl substituents having 1 to 6 atoms of carbon, preferably 1 to 4 carbon atoms, more preferably having 3 or less carbon atoms and the most preferably they have less than 3 carbon atoms.

When naphthenes are present, they can be saturated or unsaturated. Preferred naphthenes comprise 6 to 20 carbon atoms, more preferably from 6 to 12 carbon atoms, for example from 6 to 8 carbon atoms. Specific examples include cyclopentane, methylcyclopentane, dimethylcyclopentane (per example 1,1-dimethylcyclopentane, 1,2-dimethylcyclopentane and 1,3-dimethylcyclopentane), ethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane and n-pentylcyclohexane.

Preferably, the naphthene content of the hydrocarbon feedstock is 0 to 60% by weight, plus preferably from 25 to 50% by weight and most preferably from 30 to 40% by weight. In a more preferred embodiment, the material of Naphtha feed comprises from 10 to 35% by weight, preferably 15-25% by weight of methylcyclohexane. The material of Naphtha feed can also comprise cyclohexane (by example, 1 to 5% by weight), 1,1-dimethylcyclopentane (for example 1 to 5% by weight) and / or 1,3-dimethylcyclopentane (for example, from 2 to 10% in weight).

When aromatic compounds are present, they can comprise 6 to 20 carbon atoms, preferably 7 at 12 carbon atoms. Specific examples include benzene, toluene, dimethylbenzene, ethylbenzene and n-butylbenzene. Preferably, the content of aromatic compounds of the hydrocarbon feedstock it is 0 to 10% by weight, more preferably 1 to 5% by weight. In a most preferred embodiment, the naphtha feedstock it comprises 0 to 5% by weight, preferably 0 to 2% by weight of benzene and / or toluene.

In a preferred embodiment, the material of Food includes both naphthenes and aromatic compounds. The rest of the hydrocarbon feedstock can Understand non-cyclic paraffins. Such paraffins can form of 1 to 99% by volume of hydrocarbon feedstock total. Preferably, such paraffins form at least 30% in volume, for example 50 to 80% by volume, more preferably of 6 to 80% by volume of the hydrocarbon feedstock. The non-cyclic paraffins can have 4 to 20 carbon atoms, preferably from 6 to 10 carbon atoms and more preferably from 6 to 8 carbon atoms. Examples of non-cyclic alkanes that may be present in the feeding material include iso-pentane, 3-methylpentane, n-hexane, 2,2-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 2,3-dimethylpentane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, n-heptane, dimethylhexane and methylheptane.

In a preferred embodiment, the material of hydrocarbon feed is a stream of gasoline that comprises a major proportion of C7 hydrocarbons and an amount less than a C5, C6 and / or C8 hydrocarbon. Examples of C5 hydrocarbons that may be present include iso-pentane Examples of C6 hydrocarbons which may be present include 3-methylpentane, n-hexane, cyclohexane and benzene. Examples of C7 hydrocarbons that may be present include 2,2-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 1,1-dimethylcyclopentane, 1,3-dimethylcyclopentane, 2,3-dimethylpentane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, n-heptane, methylcyclohexane and toluene. Examples of C 8 hydrocarbons that may be present include dimethylhexane and methylheptane. Feeding material hydrocarbon can comprise:

25 to 40% by volume of n-heptane;

10 to 28% by volume of a C_ {7} monoraramified;

5 to 15% by volume of a C_ {7} dirramified;

20 to 40% by volume of naphthenes and

0 to 5% by volume of compounds aromatic

In the pretreatment stage, the material of hydrocarbon feed is contacted with a catalyst in the presence of hydrogen. Under the reaction conditions, at minus some of the annular structures C 5 and / or C 6 present in the hydrocarbon feed material open selectively to form linear aliphatic structures or branched. For example, any methylcyclohexane present in the hydrocarbon feed material becomes preferably in 2,4-dimethylpentane.

Such ring opening reactions have the effect of reducing the number of ring structures in the material of hydrocarbon feed, while preferably avoid significant misalignment of any pendant ring substituents. Thus, in preferred modalities of the invention, there is substantially no fragmentation of the cyclic compound The selectivity of the formation reaction of ring is preferably 10%, preferably at least 50%, per example of 80 to 99%.

In addition to the ring opening reaction described above, preferably, the addition of hydrogen through unsaturated bonds. This can be done. by transposition reactions. For example, any Benzene present in the feedstock is hydrogenated preferably under the reaction conditions to form cyclohexane This cyclic compound can "open" to continuation to produce, for example, 2-methylpentane

Suitable ring opening catalysts They contain both a metallic function and an acidic function. The Metallic function can be presented using an effective amount of a Group VIII metal. Suitable Group VIII metals include Fe, Ru, Os, Co, Rh, Ir, Ni, Pd and mixtures thereof. Of these, it They prefer Rh, Ir and Ru. Ir is particularly preferred. amount of metal used can vary from 0.01 to 10% by weight, preferably from 0.02 to 5% by weight, more preferably from 0.05 to 3% by weight and most preferably 0.1 to 1% by weight.

The acid function can be provided by A zeolitic material. Such zeolitic materials can be used to support the metals described above. Preferably, the zeolitic material is of the faujasitic type that has a Si / M ratio of at least 30, where M is at least one element selected from Al, Ga, B, Zn, Re and Cr. Preferably, M is Al and the Si / Al ratio of the zeolitic material is at least 60. Examples of preferred zeolitic materials are described in US 4 714 601 (materials ECR-4), US 4 879 103 (materials ECR-30), US 4 931267 (materials ECR-32), US 5 116 590 (materials ECR-35), US 3 415 736 (materials ZSM-3) and US 3 972 983 (materials ZSM-20). Analogues of such can also be used. zeolites, such as EMC-1 and EMC-2 (Delpratop et al., Zeolites, 10, p 546-552 (1990)). Other examples of suitable zeolitic materials include mordenite, Y, beta, MCMs, clay, montmorrillonitic materials and ITQ-6 materials. An ITQ-6 material it is an oxide that in its calcined form has a diagram of X-ray diffraction that includes the figures in the table below. The material has a specific microporous surface of ITQ-6 (as determined by the method of adsorption-desorption of N2) of at least 400 m2 / g and a specific external surface (also determined by the adsorption-desorption method of N 2) of at least 350 m2 / g. The materials ITQ-6 are described in detail in PCT / GB / 99/02567, which is incorporated here by reference.

TABLE

d (Angstroms) I / Io * 100 9.50 +/- 0.19 F 7.10 +/- 0.14 F 6.62 +/- 0.13 m 5.68 +/- 0.11 d 3.97 +/- 0.08 F 3.73 +/- 0.07 F 3.53 +/- 0.07 mf 3.16 +/- 0.06 m

In this table, the letters indicate what next:

f = strong 40-60% relative intensity

mf = very strong 60-100% relative intensity

m = average 20-40% relative intensity

d = weak 0-20% relative intensity

The pretreatment stage is carried out preferably at 150 to 400 ° C, more preferably at 225 to 350 ° C Pressures from 0 to 208.6 gauge bars can be used (from 0 to 3000 psig), preferably from 6.9 to 151.7 bar gauge (100 to 2200 psig) and more preferably 6.9 to 103.4 gauge bars (100 to 1500 psig). The material of hydrocarbon feed can be passed over the catalyst  at a liquid hourly space velocity of 0.1 to 10, preferably 0.5 to 5 LHSV (h -1). In one mode preferred, the speed of the hydrogenated treatment gas is maintains 60 to 2000 m3 of hydrogen per m3 of hydrocarbon reactant, preferably 100 to 600 m3 of hydrogen per m3 of hydrocarbon reactant.

Ring opening reactions are described in general in WO 97/09288, WO 97/09290 and US 5 763 731.

Once pretreated, the feeding material hydrocarbon is contacted with a catalyst of isomerization to produce a product stream containing triptane

The isomerization catalyst used is preferably a super acid. Suitable superacids include Lewis acids of the formula MX_ {n}, where M is an element selected from Group 13, 14, 15 and 16 of the Periodic Table, X is a halogen and n is an integer from 3 to 6. Preferably, M is select from Groups 13 and 15 of the Periodic Table. Plus preferably, M is Sb, X can be F, Cl, Br or I, and, preferably, it is F or Cl. In preferred embodiments of the invention, M is used in its highest valence state with the halogen selected. Thus, in a more preferred embodiment of the invention, the Lewis acid is SbF5.

Preferably, Lewis acid is used in combination with a Bronsted acid, for example HX (where X is a halogen), fluorosulfuric acid, trifluoromethanesulfonic acid and / or trifluoroacetic acid. Preferred examples of catalysts of Suitable isomerization are HSO 3 F-SbF 5 and SbF5 -HF. The acid molar ratio of Bronsted to Lewis acid can vary from approximately 20: 1 to 1: 5. Preferably, a molar ratio of 5: 1 to 1: 1 is used. The amount of catalyst used with reference to the amount Total hydrocarbon used can vary from about 0.01 to 100 parts by weight of the catalyst per part by weight of hydrocarbon. Preferably, the amount of catalyst employed is 1 to 10 parts by weight of the catalyst per part by weight of the hydrocarbon.

The catalyst can be used as the liquid pure, as a dilute or adsorbed solution on a solid support.  With respect to the diluted catalyst, any diluent that is inert under the reaction conditions. For to obtain optimal results, the diluents can be pretreated to remove catalyst poisons such as water, compounds unsaturated and similar. Typical diluents include chloride sulfuryl, sulfuryl fluoride, fluorinated hydrocarbons and mixtures thereof. Protic acids, including fluorosulfuric acid, sulfuric acid, trifluoromethanesulfuric acid and the like can use themselves as diluents. The volume ratio of diluent: catalyst can vary from about 50: 1 to 1: 1 and preferably from 10: 1 to 2: 1.

The catalyst can be incorporated alternatively with a suitable carrier or solid support. May use any solid catalyst support that is substantially inert to the catalyst under the conditions of reaction. The support can be pretreated, such as by heating, chemical treatment or coating, to remove substantially all of the water and / or hydroxylic sites that may be present Active supports can be made inert coating them with an inert material such as trifluoride antimony or aluminum trifluoride. Suitable solid supports they include resins treated or coated with fluoride, such as sulfonated cationic exchange resins, acid chalcides, such as alumina and aluminosilicates, treated with fluoride, and acid resistant molecular sieves, such as zeolite, by example, faujasita. Supported catalysts can be prepared in any suitable way, such as by methods Conventional including dry mixing, coprecipitation or impregnation. In one embodiment, the supported catalyst is prepared. impregnating a suitable deactivated support with a metal fluoride such as antimony pentafluoride and then with an acid of Bronsted such as fluorosulfuric acid.

When a supported catalyst is used, the Lewis weight ratio to support may vary from 1: 100 to 1:10 and preferably 1:50 to 1:35. Weight ratio from Bronsted acid to the support can vary from 1: 100 to 1:10 and, preferably, from 1:50 to 1:35.

The isomerization reaction can be brought to out at -50 to 100 ° C. Preferably, the reaction temperature is from -30 to 25 ° C, more preferably from -25 to 10 ° C, even more preferably from -15 to 5 ° C, most preferably from -10 to 0 ° C

The contact time can be from 0.01 to 150 hours, preferably from 0.05 to 50 hours, more preferably from 0.08 to 24 hours, even more preferably 0.1 to 15 hours and most preferably 4 to 6 hours.

Preferably, the selectivity for the Tryptan is at least 7%, more preferably at least 9%. By For example, the selectivity for triptane can be between 9 and 60% of the initial hydrocarbon feed material.

Conditions to isomerize materials hydrocarbon feed are described in general terms in GB 0024888.0 (published as WO 02/31089) and US 3 766 286.

Claims (16)

1. A procedure for the production of triptane, said procedure comprising:

provide a hydrocarbon feedstock comprising at least 1% in moles of at least one cyclic hydrocarbon comprising a ring C 5 and / or C 6;

preheat the hydrocarbon feed material by contacting the hydrocarbon feedstock with a catalyst in presence of hydrogen, under suitable conditions to open selectively the cyclic hydrocarbon ring; and

isomerize the pretreated feed material by contacting the material feed pretreated with an isomerization catalyst to produce a product stream containing triptane.

2. A procedure in accordance with the claim 1, wherein the feedstock hydrocarbon is a hydrocarbon stream that boils in the range of 50 to 110 ° C. 3. A procedure in accordance with the claim 2, wherein the hydrocarbon stream is a rented stream or a gasoline stream. 4. A procedure in accordance with the claim 3, wherein the naphtha stream comprises at least  30% by weight, preferably at least 50% by weight, for example of 60 to 90% by weight of C7 hydrocarbons. 5. A process according to any one of the preceding claims, wherein the hydrocarbon feedstock comprises from 2 to 60% by volume, more preferably from 5 to 40% by volume and more preferably from 10 to 30% by volume of at least one cyclic hydrocarbon having a C5 ring and / or
C_ {6}. 6. A procedure according to a any of the preceding claims, wherein the al less a cyclic hydrocarbon is selected from naphthenes and aromatic compounds, optionally substituted, for example, with alkyl substituents having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, more preferably than they have 3 or less carbon atoms and most preferably that They have less than 3 carbon atoms. 7. A procedure in accordance with the claim 6, wherein, independently, the naphthenes they comprise from 6 to 20 carbon atoms, more preferably from 6 to 12 carbon atoms, for example 6 to 8 carbon atoms, and aromatic compounds comprise 6 to 20 carbon atoms, preferably from 7 to 12 carbon atoms. 8. A procedure in accordance with the claim 7, wherein the at least one cyclic hydrocarbon is select from the group consisting of cyclopentane, methylcyclopentane, dimethylcyclopentanes (for example 1,1-dimethylcyclopentane, 1,2-dimethylcyclopentane and 1,3-dimethylcyclopentane), ethylcyclopentane, cyclohexane, methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, n-pentylcyclohexane, benzene, toluene, dimethylbenzene, ethylbenzene and n-butylbenzene. 9. A procedure in accordance with the claim 1, wherein the feedstock hydrocarbon comprises: 25 to 40% by volume of n-heptane; 10 to 28% by volume of a C_ {7} monoraramified; 5 to 15% by volume of a C_ {7} dirramified; 20 to 40% by volume of naphthenes and 0 to 5% by volume of compounds aromatic 10. A procedure according to a any of the preceding claims, wherein the ring opening catalyst contains both a function Metallic as an acid function. 11. A procedure in accordance with the claim 10, wherein the metal function is presented using an effective amount of a Group VIII metal, selected preferably from the group consisting of Fe, Ru, Os, Co, Rh, Ir, Ni, Pd and mixtures thereof. 12. A procedure in accordance with the claim 10 or claim 11, wherein the acid function  It is provided by a zeolitic material. 13. A procedure according to a any of the preceding claims, wherein the Isomerization catalyst is a super acid. 14. A procedure in accordance with the claim 13, wherein the superacid is a Lewis acid of the formula MX_ {n}, where M is a selected element of the Group 13, 14, 15 and 16 of the Periodic Table, X is a halogen and n is a integer from 3 to 6. 15. A procedure in accordance with the claim 14, wherein the Lewis acid is used in combination with a Bronsted acid. 16. A procedure in accordance with the claim 15, wherein the Bronsted acid is HX (wherein X is a halogen), fluorosulfuric acid, acid trifluoromethanesulfonic acid and / or trifluoroacetic acid.